Hi ICIrisheyes! Welcome to 3FC!
Knee injuries are pretty common and they can be worked through. Your doctor should have advice for you on exercise, but I would say that you could almost definately swim as that's pretty easy on the joints. There are other exercises that are designed to be easy on the joints as well, I think cycling/spinning is supposed to be pretty gentle. As you lose weight its likely that you can gradually increase the strength of your knee and be able to do at least some of the exercises you used to do (although snow boarding might be out, from my experience its pretty hard on the knees >.<)
Im not sure about the Safeway foods, we dont have them here, but if they are designed to help with dieting they could be a good start. Check the labels and calorie content, and make sure they have enough nutrients etc. I would also cook things for yourself too, this site has good recipe ideas, healthy cooking is actualyl good fun
I never used to cook before i tried to lose weight, now i can make a decent meal out of a tin of tomatoes and a few vegetables
When i started out, i wanted to lose around 20-30kg, which i think is 44-66 pounds. Ive managed to lose around 33 pounds so far, so it is possible! You can do this, take the time to surf the site, the knowledge here is invaluable